Container constructions particularly of the drawn and ironed metal type which are easily held in one hand and used to contain various products, such as, carbonated beverages, paint and related products, deodorants, household sprays, and the like, under gaseous pressure are manufactured by an industry which is so highly competitive that any change in construction which will allow the use of less metal without sacrificing performance capabilities or where the construction lends itself to the utilization of tooling which by ordinary previous manufacturing standards would be considered excessively worn invariably gives the manufacturer a cost advantage.
There are numerous container constructions in present use which are produced by drawing and ironing a cup-shaped or flat metal blank into a tubular cylindrical side wall having an integral bottom wall and an open end. In many of these previously proposed container constructions the bottom wall is inwardly domed so as to provide a structural configuration that will resist the tendency of internal pressure subsequently created by a product in the resulting container construction from outwardly bowing such bottom wall. However, it has been found in the process of developing this invention that a container construction which utilized fully inwardly domed bottom walls has less volumetric capacity when considering the overall length of the side wall of such a container construction. In addition, it has been found that such a container construction with an inwardly domed bottom wall has its bottom wall placed under substantial compressive stress which causes buckling of the dome upon dropping the container and as commonly occurs when dispensing products such as carbonated beverages, for example, in automatic dispensing machines wherein the containers are routinely dropped during dispensing thereof, or an entire carton of containers is dropped during normal or routine handling.
Other container constructions in present use have bottom walls which are provided with flat central portions; however, each of these container constructions has an annular portion which adjoins its side wall and extends upwardly within the side wall volume whereby this is a departure from a more ideal situation of having that portion of the bottom wall which adjoins the side wall taper inwardly toward the longitudinal axis of the container.